1,724,051 research outputs found
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
The induced travel: overview and perspectives
Full text linkThe animated debate on induced traffic is going on since long time, as the first studies on this matter go back to the first half of the XXth century.
This report intends to give an overview of this argument, analysing the historical evolution of the approaches used in the studies on the induced travel and of the models carried out to take into account this phenomenon.
The starting point will be the definition of the concept, necessary because either the lack of understanding or the misunderstanding between the different point of views can partly be generated by different meanings given to the concept; the other part of disagreement can lay on different interests involved in road construction.
Then, the overview of the studies carried out in Europe and USA will allow for the understanding of the mechanism of causality between the supply and demand and will try to answer to the questions: “does the transport user’s behaviour generate the policy makers’ decisions” or “does the policy makers’ decisions
generate the transport users’ behaviour” ?.
Lastly, some considerations about the acceptance of the analysed concept and the answer of Administrations and relative eventual interventions are given.
It emerges quite clear from this work that the behavioural responses are the real focus and that an adequate policy on the land use that drives the transport systems is the unique way to have a real sustainable development either of land use or of infrastructures. To manage the transport demand through land use could control the transport demand, deviating it towards sustainable solutions. In addition, neglecting the induced travel effects leads to underestimate the impacts due to transport systems. That generally leads to a non-sustainable policy, deteriorating rather than improving the quality of life in urban
and extra-urban areas
Pollutant emissions estimation in road transport models
No full textThe report intends to analyse the problem regarding the combined use of transport and emissions models, to understand the impact on emissions due to mobility. The first part of the work is an overview of the transport and emission models carried out until now. The developments of these models have always followed separate routes and this fact explains the current difficulty using these models in a joined way. This is due also to the different quality of needed data: more aggregate for the transport models and very disaggregate for the emission models.
Then, the core of the work deals with a comprehensive analysis of the combined use of transport and emissions models, emphasising the problems and lacks affecting these ones and giving some critical remarks.
The main findings concern the estimation of the speed, vehicle miles travelled and operating modes, and capacity of the road. In addition, another important issue involves inconsistencies in the way the stepwise travel demand modelling process can be implemented, to understand how different aggregation schemes might affect the results of modelling. The importance of the reliability of transport data is largely demonstrated in this work.
It was found that the emission factors calculated by the model vary substantially when the travel-related inputs to the model are varied within the usual ranges of accuracy and precision expected with the current state of the practice in transport. Another important element studied is the reliability of emissions models, as average as modal (or instantaneous). Actually, the average emissions model do not enable to reliably evaluate operational improvements that smooth traffic flow such as ramp metering, signal co-ordination and many ITS strategies.
The “modal models” permit to enhance the performance of these ones, but the use of this kind of tool requires the input data mentioned above that need improved transport models. In addition, the uncertainty of the results is still a problem.
At last, some researches and relative applications have been presented to understand the possible approaches followed to improve the actual estimations of emissions. The analysis of these efforts shows that an integrated approach is still far and each researcher tends to improve some particular aspects, as the activity based framework, the assignment phase and the disaggregation of transport data.
At the end, a proposal is presented to manage the actual needs of precision under the viewpoint of “sample enumeration” technique. This is a possible approach to overcome actual difficulties and it indicates a possible way for the future research
Estimation tool of traffic pollutant emissions as a function of macroscopic driving variables
No full textThe report develop an instantaneous emission model considering both average speed and acceleration to define the emission coefficients of different vehicle typologie
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